This invention relates to a charge-load support for a glow discharge furnace.
In glow discharge-plasma thermochemical treatment apparatus, for example in apparatus for plasma carburising a charge-load or workpieces in a low pressure furnace, the furnace wall usually forms the anode of the electrical supply while the charge-load forms the cathode of the supply.
The charge load must therefore be supported within the furnace, electrically isolated from the furnace wall, and have an electrical connection thereto which passes through the furnace wall.
A difficulty which arises in such a furnace is that during plasma carburising, electrically conductive desposits such as soot or sputter products can build-up within the furnace and provide short-circuit tracking paths for the electrical supply, thereby disturbing the glow discharge or at worst rendering the furnace inoperative.
Any build up of such conductive deposits can affect both the leadthrough electrical supply connection to the charge-load support, and the charge-load support itself.
In U.S. Pat. application Ser. No. 702,159, now abandoned, there is described and claimed a leadthrough arrangement which overcomes the difficulties of conductive deposit build-up.